The present disclosure relates to an inverter control device that controls a rotary electric machine drive device that includes an inverter, and to a vehicle control device that includes the inverter control device.
An inverter that performs electric power conversion between DC power and AC power is interposed between an AC rotary electric machine and a DC power source in many cases. The rotary electric machine not only functions as a motor that outputs power using electrical energy, but also functions as an electric generator that generates electric power using kinetic energy of a wheel, an internal combustion engine, etc. Electric power generated by the rotary electric machine is regenerated and stored in the DC power source. A power source switch such as a contactor is occasionally provided between the DC power source and the inverter. When the power source switch is in an on state, the power source switch is in a conductive state, so that the DC power source and the inverter and the rotary electric machine are electrically connected to each other. When the power source switch is in an off state, the power source switch is in a non-conductive state, so that the electrical connection between the DC power source and the inverter and the rotary electric machine is blocked.
When a failure such as an overcurrent and an overvoltage has occurred in the inverter of the rotary electric machine, shut-down control is performed, for example. In the shut-down control, a switching control signal for switching elements that constitute the inverter is varied into a non-active state to bring the inverter into an off state. Japanese Patent Application Publication No. 2003-134797, for example, discloses an example in which shut-down control is performed on the basis of the result of detection by an abnormality detection circuit or an overcurrent detection circuit in an IPM (Intelligent Power Module) in which a plurality of switching elements are integrated with each other to constitute an inverter (FIG. 1 etc.).
In this way, the shut-down control is occasionally used as a scheme for fail-safe within a rated operation range of the rotary electric machine. It is known that as the rotational speed of the rotary electric machine is higher, the counter electromotive force is larger. Thus, in general, the allowable counter electromotive force and the rotational speed of the rotary electric machine corresponding to the counter electromotive force are set in consideration of the lowest value of a DC link voltage (a voltage on the DC side of the inverter) within the rated operation range and the maximum rated voltage of the inverter or the like to which the DC link voltage is applied.